You can do nothing really when you need to host a actual server and do not have a public IP address that you control.
Spectrum talks to idiots most days which is why you got the response you did. Some idiots put their pc directly on the internet and enable file sharing. That is why even on connection that allow port forwarding they block many of the microsoft ports.
If you just wanted access to a server in your house you could use something like teamviewer. It even allows file transfers. What you want is far beyond that programs ability.
Pretty much you are going to have to build your own meetme vpn system. You would get a small vpn server from a hosting company and then build a vpn tunnel from your actual server OUTBOUND...